Comments on research and other knowledge developments in occupational and public health and current events in politics related to public health, occupational health, and the environment.

Friday, March 04, 2005

Hazards of Tight Buildings Documented

BrooklynDodger found a surprisingly strong account of health effects of tight buildings in this study conducted in France.

A tight or air conditioned building presents two hazards to workers within. First, compared to natural ventilation or no mechanical ventilation, air is recirculated so there is dramatically less fresh air. [Taking recirculation into account, calculations based on ventilation manual reference values indicate there is more fresh air in a closet in your house with the door closed than in an air conditioned office.] Vapor phase contaminants, and small particle aerosols - which in France would include tobacco smoke, and perhaps the airborne products of canonical French personal hygiene practices - are endlessly recirculated. Carbon dioxide levels are usually elevated, which may effect regulation of breathing rates.

Somewhat in the direction of less risk, total mold is reduced compared to outside air. However, different mold grows in buildings and the ventilation system than is found in the environment.

A commentary in the journal issue generally concurred on the probability of the effects observed, but remarked on the surprising strength of effect. The commenter put his money on microbial contamination of ventilation systems as the cause.

The abstract is condensed here, and then supplied in full:

"In a national sample of 920 professionally active women aged 49–65 yr ... Being exposed to heating, ventilation, and air-conditioning (HVAC) systems in the workplace proved to be a risk factor for attendance at global and several specialist medical services. The adjusted odds ratio for otorhinolaryngologist attendance was 2.33 ... in the HVAC group compared with the natural ventilation group, and 1.70 ... for sickness absence. Dermatologist and global medical services attendance rates may also be higher in this group. [The investigators concluded that] exposure to HVAC systems was a strong and significant risk factor for otorhinolaryngologist attendance and sickness absence. HVAC systems are prevalent in recent office buildings and have been shown to be associated with several adverse health effects in terms of morbidity and mortality [BrooklynDodger has to look for these references]. "

Objectives To assess the relationship between type of ventilation in the workplace, health services attendance, and sickness absence among middle-aged women.

Methods In a national sample of 920 professionally active women aged 49–65 yr from the SU.VI.MAX cohort, recruited from the general population in France, health services attendance and sickness absence were assessed prospectively during 1999.

Results Being exposed to heating, ventilation, and air-conditioning (HVAC) systems in the workplace proved to be a risk factor for attendance at global and several specialist medical services. The adjusted odds ratio for otorhinolaryngologist attendance was 2.33 (95% CI = 1.35–4.04) in the HVAC group compared with the natural ventilation group, and 1.70 (1.13–2.58) for sickness absence. Dermatologist and global medical services attendance rates may also be higher in this group (P = 0.06 in both cases).

Conclusions Exposure to HVAC systems was a strong and significant risk factor for otorhinolaryngologist attendance and sickness absence. HVAC systems are prevalent in recent office buildings and have been shown to be associated with several adverse health effects in terms of morbidity and mortality. From a public-health perspective, our results outline the need for a quantitative assessment of the health impact of ventilation systems, taking into account the possible loss of production that exists in addition to the direct costs of medical services use.

No comments:

About Me

BrooklynDodger(s)
is (are) active in
public health science. The Dodger(s)wants (want) to
share random
and contrarian
observations on
technical matters
without involving
the Dodger(s)'s
public persona(e)or institutional
affiliation. The posts are mostly abstracts from the peer reviewed scientific literature. The comments are quick and hopefully clean efforts to place the new findings in a public health context. But remember, it's just blogging, it ain't the NAS!